1. Field of the Invention
The present invention relates generally to a transmission for industrial vehicles and, more particularly, to a system for preventing an engine from stalling when an industrial vehicle is braked, which is provided with a brake detection unit, detects the operation of the brake pedal of an industrial vehicle, which is traveling, using the brake detection unit, and causes a control unit, which operates in conjunction with the operation of a brake pedal, to determine whether the speed and engine Revolutions Per Minute (RPM) of the vehicle are equal to or less than respective preset values, and to automatically switch a shuttle valve to a neutral state or a half-clutch state, and a method of controlling the system.
2. Description of the Related Art
As generally known in the art, an industrial vehicle, such as an agricultural tractor, is configured such that a main transmission and a sub-transmission are integrally coupled in series in a transmission and, thus, a Power Take-Off (PTO) output is transmitted when the tractor is driven.
Here, the main transmission is configured such that gear trains, which are related to the forward and reverse traveling modes of the industrial vehicle, are arranged therein and is responsible for changes in speed, and the sub-transmission is responsible for increasing the range of speed for given speed stages provided by the main transmission. Here, a shuttle valve for performing the forward and reverse switching of the main transmission is mounted to the transmission.
Only when the transmission of power is interrupted by pressing a clutch pedal while pressing a brake pedal in order to stop the movement of a vehicle body during traveling, or when a shuttle valve enters a neutral state or a half-clutch state through the manipulation of the shuttle lever, does the engine of the above-described industrial vehicle maintain an idle state without stalling after braking.
However, the conventional industrial vehicle, described above, is problematic in that manipulation thereof is inconvenient because the transmission of power must be interrupted by simultaneously pressing both a clutch pedal and a brake pedal in order to stop the movement of a vehicle body during traveling, or because a shuttle valve must enter a neutral state or a half-clutch state through the manipulation of the shuttle lever. As a result, the case where beginner drivers, who are not proficient in the operation of such an industrial vehicle, accidentally stall the engine, occurs frequently.
Furthermore, in the case where the response of a driver is slow when braking is conducted, a problem occurs in that the braking distance is increased, and thus the risk of accidents is increased.
Furthermore, in the case where it is desired to stop a vehicle body when traveling on a slope, it becomes necessary for the driver to apply a large force when pressing the pedals using the feet, because both a clutch pedal and a brake pedal must be simultaneously pressed. This makes it difficult for the driver to manipulate the controls.